USB Power Delivery Disconnect Detection for Arc Reduction
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Solution Overview
Problem
In USB power delivery systems, physical disconnection of the USB connector can lead to potential differences in voltage, causing arcs that may result in irreversible damage to the source and sink devices, and existing methods are inadequate in preventing such arcs.
Innovation Solution
The implementation of a switch, capacitors, comparators, and deglitch circuits in the USB system to monitor the configuration channel for changes in voltage and determine physical disconnection based on a debounce duration, thereby preventing arcs by interrupting power transfer when a disconnect is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power delivery is enabled in USB systems, then power transfer efficiency is improved, but arc damage risk increases during physical disconnection
Solution Approach 1:
The system performs preliminary detection of physical disconnection events through the configuration channel voltage monitoring before arc damage can occur. The deglitch circuit and comparator are configured to detect disconnection events and trigger switch closure in advance, maintaining capacitive coupling during the critical transition period to prevent arcs while preserving power delivery functionality during normal operation
Solution Approach 2:
The patent introduces capacitive coupling as an intermediary mechanism between the power delivery path and the disconnection event. The first and second capacitors maintain electrical coupling during physical disconnection, serving as a mediator that prevents direct arc formation while allowing the system to detect and respond to disconnection events through voltage changes on the configuration channel
2Measurement precision
If debounce duration is extended to accurately detect physical disconnection, then detection accuracy is improved, but response time increases
Solution Approach 1:
The system dynamically adjusts the debounce duration based on the detected voltage changes on the configuration channel. The deglitch circuit is configured with adjustable timing parameters that can be optimized for different operating conditions, allowing the system to maintain high detection accuracy while minimizing unnecessary delay in responding to actual disconnection events
Solution Approach 2:
The system implements feedback through the comparator that continuously monitors the configuration channel voltage and provides real-time information about connection status. This feedback mechanism allows the deglitch circuit to accurately distinguish between transient voltage fluctuations and genuine disconnection events, improving detection accuracy without requiring excessively long debounce periods
Data Source
AI summary
An example apparatus includes: a switch having a first current terminal, a second current terminal and a control terminal, the first current terminal adapted to be coupled to a first capacitor, the second current terminal adapted to be coupled to a second capacitor; a comparator having a comparator input and a comparator output, the comparator input coupled to a configuration terminal; a deglitch circuit having a deglitch input and a deglitch output, the deglitch input coupled to the comparator output, the deglitch circuit having a deglitch duration between a first duration and a second duration; and a universal serial bus (USB) controller having a controller output and a controller input, the controller output coupled to the control terminal, the controller input coupled to the deglitch output.